To provide a miniaturizable and compactly constructible heat exchanger for reducing a pressure loss.

This heat exchanger uses a plurality of porous flat tubes 222 formed by extrusion molding as a tube for flowing a high pressure refrigerant, and has a header tank 225 for communicating with the inside of the plurality of porous flat tubes 222, and distributing-supplying the high pressure refrigerant to the plurality of porous flat tubes 222, and a header tank 226 for communicating with the inside of the plurality of porous flat tubes 222, and collecting- recovering the high pressure refrigerant flowing out of the plurality of porous flat tubes 222. The high pressure refrigerant is made to flow in parallel in the plurality of porous flat tubes 222. Thus, the heat exchanger 220 is miniaturized and compactly constituted by forming a passage of the high pressure refrigerant in a multilayer (multi-path) shape.